As usual I am late to this conversation but will "chip" in:
PPF protects paint while ceramic coat aids in cleaning.
I had a 2005 MB SLK350 that I bought new and had 3M "Clearbra" installed at dealership. Fifteen years later in 2020 I removed the plastic film. The film had slightly yellowed (that problem has been solved). The film had many slices, scrapes chips in it and was difficult to remove because of the scrapes, however, under the film, the paint was showroom perfect. So perfect that the dealerships thought it was a much newer model and gave me a phenomenal trade-in price.
When my C8 arrived I had no doubt I was going to get Xpel installed and the only decision was how much of the car to cover. In the end full coverage was not that much more than partial and I knew from C4 Coupe that taking roof on and off could lead to scratches so went full coverage. I also tend to keep cars a long time so amortized over say 10 years its about $400/year.
It's really difficult to estimate cost of PPF because a lot of the cost is in paint correction and installation. Some cars don't need much and some colors will show up any small scratch. Rapid Blue shows any defect/chip because the car is white underneath. Take your car to the PPF Installer who will have bodyshop lights that show how much correction is needed. Mine needed a lot.
I have had my car at a few Corvette shows and honestly cannot tell which ones had ceramic and which did not. My opinion is that ceramic coat aids in cleaning but I am not convince the "shine" is better. Of course you still need to wash the car when dirty so frequency of washing is not reduced. I find the dirtiest area is the tail end around grill and taillights.
Most ceramic coatings require a yearly maintenance and that is significant work/cost. My decision was to try a DIY hybrid wax/ceramic
General PDP Template They now offer a graphene wax but I have not tried.
The DIY ceramic wax was easy to apply. Washing is still washing so not much better but drying is about 1/4 the time. An application seems to last about 4 months so for me that's twice a season. One container has lasted me 5 coats.
Re: exhaust sound you can select the exhaust volume and customize in some drive modes.
Re: RPM No. The engine rpm is not affected during the first 800km its just a change to the tach settings and some shift points. The 1500km note is to ensure full break-in before tracking/launching.